Scientific Forecaster Discussion
Area forecast discussion...updated
National Weather Service Gray ME
710 am EDT Sat Oct 25 2014
high pressure quickly crosses the area today before a cold front
moves through tonight. Some showers are possible as the front
crosses the region. A cool northwest flow will remain on Sunday
and Monday with upslope showers in the mountains. The next frontal
system will likely impact the area midweek.
Near term /through tonight/...
update...just a few tweaks to current temperature and sky grids to
account for latest observational trends.
Previous discussion...ridge of high pressure is quickly approaching
the area from the west this morning. Clouds and eroding from the west to
east with time. These breaks have allowed for some quickly cooling in
the CT River Valley...with patchy fog developing there.
SW flow ahead of approaching cold fnt will mean a rather mild day
in store compared to the past several. Highs should climb into the
low 60s for much of the coastal plain. Late in the afternoon cold
fnt will approach the CT River Valley...with increasing clouds and
Short term /Sunday/...
fnt will cross the forecast area with scattered showers outside of the
mountains...and precipitation likely in the higher terrain. Any mixed precipitation is
unlikely outside of the highest peaks. Clouds and increasing winds
will keep overnight temperatures mild.
Sun will feature cool...moist...nwly flow. This will lead to
significant cloudiness on the northwest slopes of the high terrain in
upslope flow. Showers will also be likely for these zones...with
some mixing in the highest elevations. Day time heating will lead
to at least broken clouds downwind of the mountains early...and gradually
downslope clearing later in the afternoon. Highs will top out in
Long term /Sunday night through Friday/...
west/northwest flow continues Sunday night and Monday with upslope
showers in the mountains and downslope clearing toward the coast.
High pressure crests over New England Monday night... allowing the
winds to subside and likely result in good radiational cooling
conditions. However... dewpoint values will still be in the
middle/upper 30s so it will not get all that cold.
Surface high moves east on Tuesday and upper ridge builds over the
northeast. Warmer air will be moving in aloft though cloud cover
will also be increasing ahead of the next upper trough.
Cold front moves through on Wednesday with cooler air moving in
behind it. High temperature forecast on Wednesday will be a bit
tricky as it depends on the timing of the frontal passage...
especially toward the coast. It is possible that temperatures
could warm into the upper 60s/low 70s before the front moves
through. But if it arrives a bit earlier then such warmth will not
be realized at the surface. Cool high pressure builds in for
Models diverge on how to handle the next trough moving through the
continent this week... arriving in New England at the end of the
week. For now the forecast will show a chance of precipitation as
the trough moves into the area... though timing and temperature
forecasts are still very uncertain.
Aviation /11z Saturday through Wednesday/...
short term...high pressure is moving into the region this
morning...allowing for partial clearing from the west. This is going
to promote some valley fog...especially in the CT River
Valley...through dawn. Kleb and khie will see tempo LIFR conditions.
VFR conditions dominate today ahead of approaching cold fnt. Late
this afternoon and tonight some MVFR conditions are possible in
showers as fnt crosses the area from west to east. Extended period of
MVFR will linger on the northwest slopes of the mountains into Sun afternoon.
Long term...MVFR conditions may continue north of the mountains
into Monday while the rest of the area remains VFR. A cold front
arriving on Wednesday may bring some brief showers and could
result in a period of MVFR conditions areawide.
short term...winds and seas continue to diminish as high pressure
quickly moves over the waters. This will be short lived...as cold
fnt crosses the waters tonight. This will bring gusty west-northwest winds in
its wake...and probable Small Craft Advisory conditions.
Long term...west/northwest winds will likely require a Small Craft
Advisory through Monday before high pressure finally crests over
the region with lighter winds. Another front arrives for Wednesday
but winds with this frontal system may stay below advisory levels.
Portland has still not had its first freeze of the fall. Average
first freeze is October 9. The record latest first fall freeze at
the jetport in Portland is October 25 set just last year. This
record will be broken again this year. Current forecast does not
have freezing temperatures in Portland through the end of the
month so this record will likely be extended by several days.
The growing season (the period between last Spring freeze and
first fall freeze) for 2014 stands at 188 days so far. This also
is a record as the previous longest growing season was 1990 (184
days). The last time freezing temperatures were recorded in
Portland was April 21.